Bookmark and Share
BioAssay: AID 1474

Quantitative High-Throughput Screen for Enhancers of SMN2 Splice Variant Expression: Summary

Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron protein SMN. The SMN locus on chromosome 5q13 contains two inverted copies of SMN called SMN1 and SMN2 which are 99% identical at the amino acid level. SMN1 is a fully functional protein and SMN2 skips exon 7 90% of the time. Skipping of exon 7 produces non-functional protein product. 10% of the SMN2 more ..
_
   
 Tested Compounds
 Tested Compounds
All(37)
 
 
Probe(2)
 
 
Active(17)
 
 
Inactive(15)
 
 
Inconclusive(6)
 
 
 Tested Substances
 Tested Substances
All(38)
 
 
Probe(2)
 
 
Active(17)
 
 
Inactive(15)
 
 
Inconclusive(6)
 
 
AID: 1474
Data Source: NCGC (SMN2003)
BioAssay Type: Summary, Candidate Probes/Leads with Supporting Evidence
Depositor Category: NIH Molecular Libraries Probe Production Network
BioAssay Version:
Deposit Date: 2009-01-02
Modify Date: 2010-11-02

Data Table ( Complete ):           Active    All
Target
BioActive Compounds: Chemical Probe: 2    Active: 17
Depositor Specified Assays
Show more
AIDNameTypeComment
1458qHTS Assay for Enhancers of SMN2 Splice Variant ExpressionconfirmatoryPrimary qHTS screen for enhancers of SMN protein production from SMN2 gene.
1733Counterscreen Assay for Enhancers of SMN2 Splice Variant Expression: Interaction with Luciferase ReporterconfirmatoryCounterscreen for inhibitors of luciferase purified enzyme.
1739Counterscreen Assay for Enhancers of SMN2 Splice Variant Expression: Modulation of SMN1 ExpressionconfirmatoryAssay for modulators of SMN protein production from SMN1 gene.
1740Confirmation Concentration-Response Assay for Enhancers of SMN2 Splice Variant ExpressionconfirmatoryConfirmation screen for enhancers of SMN protein production from SMN2 gene.
2513Counterscreen Assay for Enhancers of SMN2 Splice Variant Expression: Modulation of SMN1 Expression for Probe SARconfirmatoryAssay for modulators of SMN protein production from SMN1 gene.
2514Confirmation Concentration-Response Assay for Enhancers of SMN2 Splice Variant Expression for Probe SARconfirmatoryConfirmation screen for enhancers of SMN protein production from SMN2 gene.
2515Counterscreen Assay for Enhancers of SMN2 Splice Variant Expression: Interaction with Luciferase Reporter for Probe SARconfirmatoryCounterscreen for inhibitors of luciferase purified enzyme.
488832Confirmation Concentration-Response Assay for Enhancers of SMN2 Splice Variant Expression for Further Probe SARconfirmatoryConfirmation screen for enhancers of SMN protein production from SMN2 gene.
488821Counterscreen Assay for Enhancers of SMN2 Splice Variant Expression: Modulation of SMN1 Expression for Further Probe SARconfirmatoryAssay for modulators of SMN protein production from SMN1 gene.
488838Counterscreen Assay for Enhancers of SMN2 Splice Variant Expression: Interaction with Luciferase Reporter for Further Probe SARconfirmatoryCounterscreen for inhibitors of luciferase purified enzyme.
687012Extended Characterization of SMN2 Inhibitors: Righting Time Studiesother
687011Extended Characterization of SMN2 Inhibitors: Body Weight Studiesother
504776Enhancers of SMN2 Splice Variant Expression: Metabolic Stability in presence of NADPH Profilingother
504779Enhancers of SMN2 Splice Variant Expression: Efflux Ratio Profilingother
504778Enhancers of SMN2 Splice Variant Expression: Caco-2 Permeability Profilingother
687010Extended Characterization of SMN2 Inhibitors: Survival Studiesother
504777Enhancers of SMN2 Splice Variant Expression: Metabolic Stability in absence of NADPH Profilingother
Description:
NIH Chemical Genomics Center [NCGC]
NIH Molecular Libraries Probe Production centers Network [MLPCN]

MLPCN Grant: R03 MH084179-01
Assay Submitter (PI): Elliot Androphy

NCGC Assay Overview:

Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron protein SMN. The SMN locus on chromosome 5q13 contains two inverted copies of SMN called SMN1 and SMN2 which are 99% identical at the amino acid level. SMN1 is a fully functional protein and SMN2 skips exon 7 90% of the time. Skipping of exon 7 produces non-functional protein product. 10% of the SMN2 protein includes exon 7 and is fully functional. In the SMA disease state, mutations in the SMN1 locus are the cause of the disease state. Because only 10% of SMN2 is of the fully functional form, it is not sufficient to overcome the deficiency produced by the loss of the SMN1 product. A therapy that either increase the amount of SMN2 product made or to increase the inclusion of exon 7 has been proposed for the treatment of SMA.

We have designed an assay to identify small molecules that can increase the amount of functional SMN2 product by appending a luciferase reporter gene after the native SMN2 gene, such that inclusion of exon 7 in the expressed product places the luciferase sequence in frame, thus generating functional luciferase enzyme.
Protocol
Please refer to other AIDs (1458, 1733, 1739, 1740, 2513, 2514, 2515) for detailed assay protocols. Western blot protocol details are given in PMID: 15555999.
Comment
This summary is written for the purposes of summarizing the probe activities from the project. MLSCN probes are given a score of 100. Molecules in the prior art are given a score of 80. Other, less active molecules in the same chemical series as the probe molecules are given a score of 50. Molecules pending validation are given a score of 10. Inactive analogues from these series are given a score of 0. The present results represent the lead series after confirmation of enhanced SMN protein production in a patient derived fibroblast model. ML104 (CID 6404603) and ML153 (CID 990823) were declared as probes from this project.
Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
ScoreThe BioAssay activity ranking scoreInteger
1Activity SummaryNature of interaction of the sample with the receptor.String
2SMN Protein Expression in Patient Derived FibroblastsA description of results from a Western Blot for SMN protein in patient derived fibroblasts after incubation with compounds according to details in PMID 15555999.String
3SMN2 Reporter Assay AC50The concentration of sample yielding half-maximal enhancement of alternate splice form expression in a luciferase-based reporter assay.FloatμM
4Luciferase IC50The concentration of sample yielding half-maximal inhibition of purified luciferase in an in vitro assay.FloatμM
5SMN1 Reporter Assay IC50The concentration of sample yielding half-maximal modulation of alternate splice form expression in a luciferase-based reporter assay.FloatμM
Additional Information
Grant Number: R03 MH084179-01

Data Table (Concise)
Classification
PageFrom: